Integrated nozzle

ABSTRACT

An aircraft engine exhaust nozzle system having thrust vectoring capability for use in flight path management, for in-flight thrust reversal or modulation, or for thrust reversal during landing; and which includes a variable area nozzle for improved propulsion efficiency. The preferred embodiment utilizes an exhaust passageway having a rectangular nozzle exit area for minimum base area, boattail, and interference drag. An aerodynamically shaped plug is centrally located in the path of the exhaust gases. The portion of the plug extending aft of the nozzle exit plane is used as a thrust vector control means and comprises a pair of oppositely facing surfaces which can be displaced for changing the flow pattern of the exhaust gases, thereby generating a thrust vector for use as a primary flight control in rotating the aircraft about one of its major axes. The oppositely facing surfaces can also be positioned for forward thrust modulation or for full reversal of the thrust vector. A portion of the plug extending forward of the exit plane provides for variable throat area control by displacement of plug surface panels to obtain a desired nozzle throat area and, independently, a passageway shape and exit area for improved propulsion efficiency.

United-States Patent [1 1 Goetz 1451 Nov. 27, 1973 INTEGRATED NOZZLE[76] Inventor: Gerald F. Goetz, 3235 South 152nd St, Seattle, Wash.98188 22 Filed: Dec. 11, 1972 21 Appl. No.: 315,755

Related US. Application Data [63] Continuation of Ser. No. 68,343, Aug.8, 1970,

abandoned.

[52] US. Cl. 244/53 R, 239/265.19 [51] Int. Cl... B64d 33/04, B63h11/10, B640 15/00 [58] Field of Search 244/53; 239/265.l9,

[56] References Cited UNITED STATES PATENTS 3/1971 Denninglet a1.239/265.19 ll/l967 Colville et al 239/265.33 10/1966 Brandt 239/265.37

Primary Examiner-Trygve M. Blix Assistant Examiner-Charles E. FrankfortA Attorney- Glenn Orlob' [57] ABSTRACT An aircraft engine exhaust nozzlesystem having thrust vectoring capability for use in flight pathmanagement, for in-flight thrust reversal or modulation, or for thrustreversal during landing; and which includes a variable area nozzle forimproved propulsion efficiency. The I preferred embodiment utilizes anexhaust passageway having a rectangular nozzle exit area for minimumbase area, boattail, and interference drag. An aerodynamically shapedplug is centrally located in the path of the exhaust gases. The portionof the plug extending aft of the nozzle exit plane is used as a thrustvec tor control means and comprises a pair of oppositely facing surfaceswhich can be displaced for changing the flow pattern of the exhaustgases, thereby generating a thrust vector for use as a primary flightcontrol in rotating the aircraft about one of its major axes. Theoppositely facing surfaces can also be positioned for forward thrustmodulation or for full reversal of the thrust vector. A portion of theplug extending forward of the exit plane provides for variable throatarea control by displacement of plug surface panels to obtain a desirednozzle throat area and, independently, a passageway shape and exit areafor improved propulsion efficiency.

6 Claims, 7 Drawing Figures PAIENTEDnnvv ma SHEET 10F 4' INVENTOR.

GER/MD E GOETZ PM'FNTFD NOV P7 I913 3.774.868 SHEET 30F 4 INVENTOR. 65/5/412 5 60572 PATENIEDunYzv I915 SHEET U [1? 4 INVENTOR.

GERALD F GOETZ fim/%4% INTEGRATED NOZZLE This is a Continuation ofapplication Ser. No. 68. 343, filed Aug. 8, 1970, now abandoned.

1. Field of the Invention This invention relates to an exhaust systemand nozzle configuration for aircraft jet propulsion engines; and, moreparticularly, to a deformable plug type rectangular nozzle incorporatingthrust vectoring capability and a variable area nozzle passageway.

2. Description of the Prior Art In the design of aircraft propulsionsystems, nozzle base area, boattail and interference drag havetraditionally been responsible for severe performance and rangepenalties. This has been particularly true in the case of axi-symmetrictwin jet engine installations wherein a pair of generally cylindricalengines are mounted in a side-by-side parallel spaced relationship. Inmulti-jet engine systems, it has been customary to provide, andacceptthe weightpenalty for, individual structural assemblies, and thrustreverser mechanisms for'each engine. Such rcverser mechanisms arenormally functionally limited to use in ground roll deceleration, andtherefore inherently represent a substantial weight penalty in terms oftheir limited use in the life of the airframe.

It is the primary object of this invention to teach the use ofintegrated airframe-exhaust system structure for purposes of reducingoverall airplane weight and to improve the installed aerodynamics byminimizing the base area, boattail, and interference drag. I i

It is a further object of this invention to teach the use of astructurally rigid and lightweight exhaust nozzle thrust vectoringsystem which can be used as a primary flight control, as in in-flightthrust reverser or modulator, or as a thrust reverser during landing.

It is a related object of this invention to teach the use rectangularexit area for reduced base area, boattail, and interference drag, andincorporating a centrally disposed deformable plug means forward of theexit plane to control passageway area and shape to thereby maximizenozzle propulsive efficiency, and a movable plug means aft of the exitplane to allow asymmetrical or symmetrical thrust vectoring for flightcontrol or for thrust reversal.

imum nozzle drag, and which will allow the use of an integrated thrustvectoring system for two or more engines.

SUMMARY The above objectives are each achieved in the preferredembodiment of this invention, which discloses an aircraft dual nozzlesystem for a pair of axisymmetric jet engines located in the aircraftfuselage empennage region. The exhaust passageways of each engineterminate at a common exit plane and are each provided with a gradualshape change from a circular section near the engine to a rectangularsection at the exit plane. An aerodynamically shaped plug means islocated aft of the exit plane and is centrally disposed to extend acrossthe path of the exiting gases from the engines. The plug means includesa pair of oppositely fac- I of an exhaust nozzle passageway having agenerally ing exterior surface means, each comprising a plurality ofpivotally interconnected rigid panels movable to vary the flow patternof the exiting gases thereby generating a thrust vector which willchange the attitude .of the aircraft for purposes of flight pathmanagement. Thrust modulation and/or reversal is achieved by synchronousmovement of the pair of oppositely facing surface means. The disclosed.nozzle system further includes nozzle area control means located forwardof the exit plane and centrally disposed in the path of the gases ineach engine passageway, comprising pivotally mounted area control panelswhich establish a desired minimum throat area, and pivotally mountedexpansion control. panels for independently changing the nozzleexpansion shape and exit area while the throat arealremains constant.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a detailed cut-awayisometric view of applicants dual nozzle system, shown positioned forcruise flight. I

FIG. 1A illustrates a twin-jet aircraft incorporating the dual nozzlesystem, with a full forward thrust vector schematically depicted by theexhaust stream positioned as shown.

FIG. 2 is an enlarged cross-section view through the dual nozzle system,showing details of the actuation systems.

FIG. 3 is a detailed isometric cut-away view of the DESCRIPTION OF THEPREFERRED EMBODIMENT The FIG. ll isometric shows an integrated dualnozzle system comprising a separate exhaust passageway l for eachengine. Each passageway ll has a circular section near the engine and asmooth transition to a generally rectangular section at the nozzle exitplane, defined by the aft end portion of integrated structure 2. Theexhaust passageways l for each engine terminate at a common exit plane,and in the case of a thrust augmented or after burning system arepreferably provided with a conventional cooling air passage along theboundary wall 3. The rectangular exhaust exit plane permits a groupingof dual or multiple engines and exhaust passageways while minimizingbase area, boattail,

and interference drag. Centrally located in the path of the exhaustgases is a plug means 4 which comprises a forward plug 5 located withineach engine passageway 1, and an aft plug thrust vector control system25 located aft of the exit plane to serve both engines.

The forward plug 5 functions as a variable area nozzle and expansioncontrol means and comprises a lead ing edge heat shield 6, throat areacontrol panels 7, and expansion control panels 8. These items aresupported by carry through structural members 9 and 10 which areattached to the sidewalls of passageway 1. In the case of thrustaugmented engines, cooling air passageways are preferably provided alongthe surfaces of the plug means 4. Such cooling passageways can be fed acooling medium from any convenient source, and could be interconnectedwith the cooling passageways of boundary wall 3.

As will become more apparent in the discussion connected with subsequentfigures, the thrust vector control system 25 comprises a two-dimensionaldeformable plug centrally located in the exhaust stream aft of the exitplane and extending across the path of the gases exiting from bothengines. The thrust vectorcontr'ol system 25 is supported at its forwardend by structural means 26 and extends to a fixed trailing edgestructural means 27. Positioned as shown, the thrust vector controlsystem 25 is neutralized for full forward thrust; i.e., it forms asymmetrical aerodynamic continuation of each of the forward plugs 5located in the enginepassageways 1.

FIG. 1A illustrates a twin jet aircraft incorporating the dual nozzle.The exhaust stream is schematically depicted in the full forward thrustposition for cruise or high speed flight. In the aircraft embodimentshown, the engines are placed side-by-side in the fuselage empennageregion where the entire nozzle system may be integrally constructed as acontinuation of the fuselage structure, thereby creating an extremelyrigid and relatively lightweight structural system inherently capable ofsustaining repeated loadings with minimum deformation;

FIG. 2 is an enlarged sectional view through the dual nozzle, showingthe details of construction of the actuation system. A series of forwardhinge fittings 11 are connected to structural member 9 to allow pivotalmotion of area control panels 7 when forces are applied to the panels ataft hinge fittings 12 by a nozzle area control actuation system 13 whichcomprises connecting links 14, crank arms 15, pneumatic drive motors 16,power transfer synchronizing shafts l7, and a position feedback control(not shown) which is operably responsive to signals from the aircraftpropulsion control system.

Forward hinge fittings 18 of the expansion control panels 8 arepivotally interconnected with the nozzle area control actuation system13 at the aft hinges 12 of the area control panel 7. The expansioncontrol panels 8 are connected to an expansion control actuation system20 via aft hinge fittings 19. Expansion control actuation system 20comprises floating connecting links 21, crank arms 22, a pneumatic drivemotor 23, power transfer synchronizing shaft 24, and a position feedbackcontrol (not shown) which is operably responsive to the aircraftpropulsion control system.

Minimum nozzle throat area is established by a synchronous outwardrotation of the actuator crank arms 17 rotatably driving the nozzle areacontrol panel 7 outwardly about the forward hinge fitting 11, uponcommand of the aircraft propulsion control system. Increased nozzlethroat areas may be selectively achieved by an inward synchronousrotation of the actuation crank arms 15, reversing the aforementionedmovements and collapsing the nozzle area control panels 7 to a desiredthroat area consistent with maximum propulsive efficiency.

It should be noted that the nozzle area control panel 7 and theexpansion control panel 8 are operated independently to first achieve adesired throat area by rotation of panel 7, and then a desired expansionshape and exit area by rotation of panel 8 with respect to panel 7 inorder to optimize the performance of the engine. The solid line positionof expansion control panels 8 shown in FIG. 2 represent the maximumexpansion, or closed position. For nozzle conditions requiring lessexpansion, the panels 8 may be rotated upon command of the propulsioncontrol system to drive motor 23, which causes an outward rotation ofcrank arms 22 and consequent movement of links 21 to synchronouslyrotate panels 8 outwardly toward the dotted line positions shown.

As noted previously, the preferred embodiment of Applicants multi-jetnozzle system utilizes separate variable area and expansion controlmeans for each engine passageway, in combination with a single thrustvector control system 25 incorporated into the trailing portion of thedual function plug means 4. It should be apparent that this use of asingle thrust vector control mechanism for a plurality of engines isinherently efficient from a weight and reliability standpoint. How ever,persons skilled in this art will realize that the optional provision ofindependent spaced apart thrust vector control systems for each enginewould allow differential vectoring which could be used for flightcontrol along all three major flight axes.

Thrust vector control system 25 as shown in FIG. 2 comprises a forwardstructural means 26, a fixed trailing edge structural means 27, a pairof pivot fittings 28 which independently mount upper and lower primarypanels 29 for free rotation about structural means 26, an aft hingefitting 32, upper and lower primary panels 29 for free rotation aboutstructural means 26, an aft hinge fitting 32, upper and lower secondarypanels 33, an integral rocker arm 34, secondary panel hinge 35, afthinge fitting 36, upper and lower rocker bell cranks 37, upper and lowerlip panels 38, integral rocker arms 39, lip panel hinge 40, floatingconnecting links 41; and an actuation system 42 which includesconnecting links 43, crank arms 44, pneumatic drive motors 45, and powertransfer synchronizing shafts 46.

Thrust vector control system 25 utilizes two separate actuation systems42 with a position feedback control system (not shown), to provide forindependent positioning of the oppositely facing surface means, eachcomprising a set of the pivotally interconnected rigid panels 29, 33,and 38. Upon command of the flight and propulsion control system theactuation systems 42 move panels 29, 33 and 38 to selected positions tochange the path of exhaust gases flowing past the plug. Thrustmodulation and/or reversal is achieved by synchronous symmetricalmovement of the oppositely facing surface means into positions causing asymmetrical change in the flow pattern on each side of the plug, thedotted lines shown in FIG. 2 representing full reverse thrust positions.Thrust vectoring to generate a thrust vector having an unbalanced forcecomponent tending to change the attitude of the aircraft for flight pathmanagement is achieved by displacing one of the oppositely facingsurface means with respect to the other surface means to thereby causean asymmetrical flow path of the gases.

The oppositely facing surface means as shown are each independent andidentical mechanical four-bar linkages with two rocker arms in series. Acommand of the aircraft flight and propulsion control system requestingsymmetrical thrust modulation or reversal causes the actuation of drivemotors 45 which induce a synchronous outward rotation and motion ofcrank arms 44 and connecting links 43, and rotate primary panels 29about the centerline of structural means 26 in the direction of thedotted lines. The induced and combined rotary motion of rocker arms 34due to the rotation of rocker bell crank 37 about trailing edgestructural means 27 rotates the secondary panel 33 about the centerlineof secondary panel hinge 35, thereby amplifying the angular displacementof secondary panel 33 andin turn raising the lip panel 38, induced bysecondary panel 33.. Rotation of lip panel 38 about the aft hingefitting 36 and hinge point 40 is accomplished by means of the combinedmotion of floating link 41, bell crank 37, and rocker arm 39, inducingthe lip panel 38 to rotate about hinge point 40.

A reverse mechanical motion will return the thrust vector control systemsurface means to the neutral or closed position shown in solid lines inFIG. 2. It should be noted that the mechanism is arranged such that intheevent of a complete failure of an actuation system 42, the surfacemeans will return to the neutral positionQShould a partial actuationfailure occur (as by failure of one of. two actuator motors inparallel), the power transfer synchronizing shafts 40 will permit thesystem to operate at reduced rates.

FIG. 3 is a cut-away isometric view showing the thrust vector controlsystem 25 positioned for full reverse thrust (the dotted line positionsof FIG. 2). It is evident that the gases flowing on either side offorward plugsS will be turned by the rigid panel members 29,

33, and 38, to thereby reverse the direction of the,

thrustvector by 180 for purposes of aircraft deceleration. In contrastto most prior art reverser configurations used only during landing thedisclosed vectoring system has been designed to allow thrust reversal.while the aircraft is in flight, thereby providing increased flexibilityfor maneuveringpurposes.

FIG. 3A illustrates the twin jet aircraft of FIG. 1A with the thrustvector control system positioned for reverse thrust,as in FIG. 3. Theexhaust stream path can be. seen to have been diverted to a forwarddirection over and under the empennage region of the aircraft fuselage.

FIG. 4 isa cut-away isometric showing the thrust vector control systempositioned to deliver a thrust vector having an unbalanced forcecomponent tending to pitch the aircraft nose-up about its major pitchaxis for purposes of flight path management or maneuvering.

advantages are as follows: rigidity and reliability with reduced weightthrough integration of the exhaust system with basic airframe structure;the fixed rectangular nozzle exit plane allows any number of engines tobe placed side by side without a nozzle base drag or boattail dragpenality; improved installed nozzle performance through throat area andexpansion area control; thrust vector modulation control independent ofengine power level; symmetrical thrust vector control for modulation andreversal over a range of from 0 to 180 from the forward thrust position;asymmetrical thrust vector control over a range of from 0 to. 180 foruseas a primary flight control in flight path management for assistingground roll rotation, thrust trimming the aircraft in cruise flight, aback-up pitch control, an inflight thrust reverser for maneuvering, andas a thrust modulator at constant engine power settings for instantflight path response.

Certain advantages useful ona military mission are inherent inapplicants nozzle systems. Most prior art nozzle systems haverelativelypredominant and easily detected radar cross-sections and infraredsignatures that are difficult to suppress, particularly from the rear.Applicants nozzle with its centrally located plug dividing the exhauststream tube, inherently provides a reduced unique and distinct infraredsignature. The plug furnishes a large and easily cooled heat sink (e.g.,cooling by ambient air scoops) to all-ow further reduction of theinfrared signatures to potentially superior levels. In addition, thecentrally disposed plug minimizes returning'radar signals and theoblique surfaces of the plug deflect such signals away from theirsource. Also, the plug inherently provides increased nozzle surfaceareas for the addition of special surface materials which can beutilized to reduce either sound, radar, or infrared characteristics.Furthermore, applicants plug means can becontrolled to vary both thedirection and intensity of these detection parameters to confusedetection devices. Therefore, in terms of infrared signature, radarcross-section, and sound suppression, the disclosed nozzle systemprovides distinct advantages over prior designs.

Upon command of the flight and propulsion control system, the uppersurface means (panels 29, 33 and 38) have been displaced outwardlywithout disturbing the lower surface means from their neutral or forwardthrust positions, as shown. This asymmetric operation results in apitching moment which can be used as a priparent that the nozzle systemof this invention offers many advantages over prior art systems. Some ofthese Many variations and modifications of the concepts disclosed willbe apparent in light of the foregoing description. For example, thedisclosed concepts have utility with single engines, horizontally orvertically stacked multiple engines, and afterburning or nonafterburningengines. The thrust vectoring control systom 25 could be simplified to arigid pivotable airfoil section if thrust modulation and reversal arenot required; or it could be modified to provide for coordinatedmovement of the upper and lower surface means (29, 33 and 38) in thesame direction by a first actuation system for thrust vectoring; and toprovide for symmetrical movement by a second and independent actuationsystem for thrust modulation and reversal. The fixed trailing edgestructural means 2'7 could .be made movable, as part of the surfacemeans, to further enhance the thrust vectoring characteristics. Also, aswas mentioned earlier, the optional provision of at least twoindependent and separate thrust vectoring control systems, e.g., one foreach of the two engines shown, would allow differential vectoring andmodulation for direct thrust control of each of the three major flightaxes for purposes of flight path management. It should be further notedthat the forward plug 5. and the aft plug 25 could advantageously bepivotally interconnected between panels 8 and 29 near the exit plane toprovide improved aerodynamic continuity and eliminate the small interimbase area which arises when the area control panel 8 is in an outwardlydisposed position. Additionally, for certain unusual flight conditions,the nozzle variable area and expansion control means of the forward plugcould be used to shift the location of the minimum throat area from theposition established by area control panels 7, to the exit plane merelyby continuing the outward rotation of expansion panels 8 past the dottedline position of FIG. 2. it should also be recognized by persons skilledin this art that the concepts disclosed may have application to vehiclesother than aircraft, and propulsive fluid mediums other than air.Accordingly, it is intended that the appended claims cover any suchvariations or modifications.

What is claimed and desired to be secured by U.S. letters patent is:

1. An engine exhaust nozzle system for use in combination with a jetengine and a vehicle having a directional control system; said systemhaving a passageway defining a generally rectangular section near theexit plane of the exhaust gases and a thrust vector control means forselectively establishing a total resultant thrust vector with anunbalanced force component normal to the direction of flow of the gasesapproaching said exit plane comprising: plug means extending aft of saidexit plane and centrally disposed in the path of the gases exiting saidpassageway and having a pair of oppositely facing surface means each ofwhich includes a primary panel independently mounted for rotation withrespect to said passageway and a secondary panel pivotally mounted onsaid primary panel near the trailing edge thereof, and a pair ofindependent actuation means for independently moving each of saidsurface means with respect to the other of said surface means to therebyasymmetrically change the external contour and shape of said plug meansand change the direction of flow of said exhaust gases; wherein saidthrust vector control means is responsive to said directional controlsystem to selectively establish a thrust vector having an unbalancedforce component tending to rotate said vehicle about one of its majoraxes for purposes of directional control of said vehicle.

2. The system of claim 1 which additionally includes lip panelspivotally attached to said secondary panels near the trailing edgethereof, and wherein reverse thrust may be achieved by synchronousmovement of each of said independent actuation means to symmetricallydisplace corresponding pairs of said primary, secondary, and lip panelsof said oppositely facing surface means .into positions wherein thegases are turned through an increasingly greater angle as they pass overeach of the pivotally interconnected panels.

3. The system of claim 1 which additionally includes variable areanozzle control means located on said plug means forward of said exitplane comprising: a pair of oppositely facing area control panels eachpivotally mounted near a forward edge, and means for concurchronouslyrotating said expansion control panels with respect to said area controlpanels.

5. in combination with ajet engine and a control system; an exhaustnozzle passageway having a generally rectangular section near the exitplane of the exhaust gases; deformable plug means attached to oppositewalls of said passageway and centrally disposed in the path of theexhaust gases forward of said exit plane; said plug means comprisingmeans for varying the throat area between said plug means and a wall ofsaid passageway and independent means for changing the shape and exitarea of said passageway while said throat area remains constant; whereinsaid means for varying the throat area within said passageway comprises:a pair of oppositely facing area control panels each pivotally mountednear a forward edge, and means for con currently and synchronouslyrotating said area control panels to thereby change the area of saidpassageway; wherein said means for changing the shape and exit area ofsaid passageway comprises: a pair of oppositely facing expansion controlpanels each pivotally attached to a respective one of said area controlpanels, and means for concurrently and synchronously rotating saidexpansion control panels with respect to said area control panels; andwherein said deformable plug means is responsive to said control systemto selectively establish a desired nozzle passageway throat area,expansion shape, and exit area for maximum propulsive efficiency.

6. In combination with a vehicle having a jet engine and a controlsystem: an engine exhaust nozzle passageway which defines a generallyrectangular section near the exit plane of the exhaust gases; thrustvector control means for selectively establishing a resultant thrustvector which has an unbalanced force component normal to the directionof flow of the exhaust gases at said exit plane comprising: plug meansextending aft of said exit plane and centrally disposed in the path ofthe gases exiting said passageway, said plug means comprising a pair ofoppositely facing surface means; each having a plurality of pivotallyinterconnected panels defining the external contour of said plug; meansfor moving said surface means to thereby change the direction of flow ofat least a portion of said exhaust gases; variable area nozzle controlmeans responsive to said control system centrally located in saidpassageway forward of said exit plane comprising: means for varying theminimum throat area within said passageway, and means for changing theshape and exit area of said passageway while said throat area remainsconstant; wherein said means for varying the minimum throat area withinsaid passageway comprises: a pair of oppositely facing area controlpanels each pivotally mounted near a forward edge, and means forconcurrently and synchronously rotating said area control panels tothereby change the minimum area of said passageway; wherein said meansfor changing the shape and exit area of said passageway comprises: apair of oppositely facing expansion control panels each pivotallyattached to a respective one of said area control panels, and means forconcurrently and synchronously rotating said expansion control panelswith respect to said area control panels; wherein said thrust vectorcontrol means includes means for thrust modulation and thrust reversalby movement of said pair of oppositely facing surface means intopositions causing a symmetrical change in the direction of flow of theexhaust gases passing on each side of said plug; and wherein said thrustvector control means is responsive to said control system to selectivelyestablish a thrust vector having an unbalanced force component tendingto rotate the vehicle about one of its major axes for purposes ofdirectional control of said vehicle.

I Patent No. 3 h8 .UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONDated N m er 27 197 5 Inventofls) GERALDF. GOETZ It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below: 7

On the cover sheet, insert ['75] Assignee: The

Boeing Company, Seattle, Washington, a corporation. of

Delaware Signed and sealed this 6th day of. August 197A.

K EALX Attest':

MccoY GIBSON, JR. Attesting Officer c MARSHALL DANN Commissioner ofPatents FORM po'wso uscoMM-oc we're-Pea I I I v V Q U.S, GOVERNMENTPRINTING OFFICE I91 OlC-JJ.

1. An engine exhaust nozzle system for use in combination with a jetengine and a vehicle having a directional control system; said systemhaving a passageway defining a generally rectangular section near theexit plane of the exhaust gases and a thrust vector control means forselectively establishing a total resultant thrust vector with anunbalanced force component normal to the direction of flow of the gasesapproaching said exit plane comprising: plug means extending aft of saidexit plane and centrally disposed in the path of the gases exiting saidpassageway and having a pair of oppositely facing surface means each ofwhich includes a primary panel independently mounted for rotation withrespect to said Passageway and a secondary panel pivotally mounted onsaid primary panel near the trailing edge thereof, and a pair ofindependent actuation means for independently moving each of saidsurface means with respect to the other of said surface means to therebyasymmetrically change the external contour and shape of said plug meansand change the direction of flow of said exhaust gases; wherein saidthrust vector control means is responsive to said directional controlsystem to selectively establish a thrust vector having an unbalancedforce component tending to rotate said vehicle about one of its majoraxes for purposes of directional control of said vehicle.
 2. The systemof claim 1 which additionally includes lip panels pivotally attached tosaid secondary panels near the trailing edge thereof, and whereinreverse thrust may be achieved by synchronous movement of each of saidindependent actuation means to symmetrically displace correspondingpairs of said primary, secondary, and lip panels of said oppositelyfacing surface means into positions wherein the gases are turned throughan increasingly greater angle as they pass over each of the pivotallyinterconnected panels.
 3. The system of claim 1 which additionallyincludes variable area nozzle control means located on said plug meansforward of said exit plane comprising: a pair of oppositely facing areacontrol panels each pivotally mounted near a forward edge, and means forconcurrently and synchronously rotating said area control panels tothereby change the minimum area of said passageway.
 4. The system ofclaim 3 which additionally includes a pair of oppositely facingexpansion control panels each pivotally attached to a respective one ofsaid area control panels, and means for concurrently and synchronouslyrotating said expansion control panels with respect to said area controlpanels.
 5. In combination with a jet engine and a control system; anexhaust nozzle passageway having a generally rectangular section nearthe exit plane of the exhaust gases; deformable plug means attached toopposite walls of said passageway and centrally disposed in the path ofthe exhaust gases forward of said exit plane; said plug means comprisingmeans for varying the throat area between said plug means and a wall ofsaid passageway and independent means for changing the shape and exitarea of said passageway while said throat area remains constant; whereinsaid means for varying the throat area within said passageway comprises:a pair of oppositely facing area control panels each pivotally mountednear a forward edge, and means for concurrently and synchronouslyrotating said area control panels to thereby change the area of saidpassageway; wherein said means for changing the shape and exit area ofsaid passageway comprises: a pair of oppositely facing expansion controlpanels each pivotally attached to a respective one of said area controlpanels, and means for concurrently and synchronously rotating saidexpansion control panels with respect to said area control panels; andwherein said deformable plug means is responsive to said control systemto selectively establish a desired nozzle passageway throat area,expansion shape, and exit area for maximum propulsive efficiency.
 6. Incombination with a vehicle having a jet engine and a control system: anengine exhaust nozzle passageway which defines a generally rectangularsection near the exit plane of the exhaust gases; thrust vector controlmeans for selectively establishing a resultant thrust vector which hasan unbalanced force component normal to the direction of flow of theexhaust gases at said exit plane comprising: plug means extending aft ofsaid exit plane and centrally disposed in the path of the gases exitingsaid passageway, said plug means comprising a pair of oppositely facingsurface means, each having a plurality of pivotally interconnectedpanels defining the external contour of said plug; means for moving saidsurface means to thereby change the direcTion of flow of at least aportion of said exhaust gases; variable area nozzle control meansresponsive to said control system centrally located in said passagewayforward of said exit plane comprising: means for varying the minimumthroat area within said passageway, and means for changing the shape andexit area of said passageway while said throat area remains constant;wherein said means for varying the minimum throat area within saidpassageway comprises: a pair of oppositely facing area control panelseach pivotally mounted near a forward edge, and means for concurrentlyand synchronously rotating said area control panels to thereby changethe minimum area of said passageway; wherein said means for changing theshape and exit area of said passageway comprises: a pair of oppositelyfacing expansion control panels each pivotally attached to a respectiveone of said area control panels, and means for concurrently andsynchronously rotating said expansion control panels with respect tosaid area control panels; wherein said thrust vector control meansincludes means for thrust modulation and thrust reversal by movement ofsaid pair of oppositely facing surface means into positions causing asymmetrical change in the direction of flow of the exhaust gases passingon each side of said plug; and wherein said thrust vector control meansis responsive to said control system to selectively establish a thrustvector having an unbalanced force component tending to rotate thevehicle about one of its major axes for purposes of directional controlof said vehicle.